Hydraulic System: Description and Operation

WARNING: Brake fluid may be irritating to skin or eyes. In case of contact, take the following action:
^ Eye contact - rinse eyes thoroughly with water.
^ Skin contact - wash skin with soap and water.

CAUTION: Brake fluid will damage electrical connections and painted surfaces. Use shop cloths, suitable containers and fender covers to prevent brake fluid from contacting these areas. Always reseal and wipe off brake fluid containers to prevent spills.

Use Delco Supreme 11 (R) Hydraulic Brake Fluid (GM P/N 1052535) or an equivalent DOT 3 motor vehicle brake fluid.

Brake fluid should always be stored in a closed, sealed container. Never use previously opened containers of stored brake fluid. Always use new fluid from a sealed container. Reseal brake fluid containers immediately after use. Brake fluid left in an open or improperly sealed container will absorb moisture. This can lower the fluid's boiling point and result in system contamination, corrosion or deterioration of rubber components.

Standard or Contaminated Brake Fluid

CAUTION: Power steering fluid and brake fluid cannot be mixed. If brake seals contact power steering fluid or steering seals contact brake fluid, seal damage will result.

No special fluids are used in this system. However, care must be taken to use the correct fluids. The master cylinder and brake system use brake fluid, while the hydraulic booster system uses power steering fluid. Improper fluid, water or any other contaminants in the fluid may cause the brake fluid to boil or rubber components to deteriorate in the hydraulic system. Swollen master cylinder piston seals show that rubber deterioration has occurred. This deterioration is also shown by swelling of wheel cylinder boots, caliper boots or the master cylinder reservoir diaphragm. If rubber deterioration is found, replace all rubber parts in the system, including the hoses. Check for fluid on the brake linings. If any is found, replace the linings. If the brake fluid is contaminated and the master cylinder piston seals are satisfactory, check for leaks or excessive heat conditions. If no leaks or excessive heat conditions are found, flush the system.

Flushing the System
Flushing the brake hydraulic system involves running new brake fluid through the system until the fluid at each bleeder valve comes out clear. This is the only way to clear contaminated fluid out of the system. The brake hydraulic system should be flushed with clean brake fluid any time new hydraulic parts are installed. Flushing is also recommended if there is any question of contamination, incorrect grade of fluid in the system or mineral oil in the fluid.